Blue-black azo dye.



UNITED STATES Patented Tune 13, 1965.,

PATENT OFFICE.

MARTIN HERZBERG, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBEN- FABRIKEN OF ELBERFELD 00., OF NEW YORK, N. Y., A CORPORATION off, and dried.

OF NEWV YORK.

BLUE-BLACK AZO DYE.

SPECIFICATION forming part of Letters "Patent No. 792,032, dated June 13, 19 05. Application filed January 12, 1905. Serial No. 240,776.

To aZZ whom it may concern.-

Be it known that I, MARTIN HERZBERG, cloctor of philosophy, chemist, (assignor to the FARBENFABRIKEN OF ELBERFELD COMPANY, of New York,) residing at Elberfeld, Germany, have invented anew and useful Improvement in New Azo Dyes; and I hereby declare the following to be a clear and exact description of my invention.

I have found that new and valuable azo dyestuffs are obtained by first combining the diazo compounds obtainable from mononitroacetyl para phenylenediamin having the formula:

with dioxynaphthalene disulfonic acids and then splitting off from the resulting dyestuffs the acetyl group by saponification.

The new dyestufls are in the shape of their alkaline salts dark powders soluble in water. They yield upon suitable treatment with stannous chlorid and hydrochloric acid triamidobenzene and amidodioxynaphthalene disulfonic acids and dye unmordanted wool from acid-baths black shades.

ln carrying out my process practically I can proceed as follows, the parts being by weight: 19.5 parts of mononitroacetyl -paraphenylenediamin having the above-given formula are diazotized in the usual manner by means of hydrochloric acid and seven parts of sodium nitrite, and the resulting diazo compound is added to a solution of thirty-two parts of 1.8- dioxynaphthalene3.6-disulfonic acid. After some time a small quantity of sodium acetate is added, and it is then stirred until the formation of the dyestufi is completed. When this point is reached, the dyestulf is precipitated by the addition of common salt, filtered It dyes wool from acid-baths violet-red shades. The coloring-matter thus obtained is then heated to boiling with eight times its quantity of afifty-per-cent. sulfuric acid in order to eliminate the acetyl group. The new azo dyestuff thus produced deposits during the heating in a crystalline shape.

The isolation of the intermediate product is not necessary. The acetyl group can also be split off by directly boiling the reaction mass with an acid or an alkali.

The new dyestuff thus obtained is in the shape of its sodium salt. a black powder soluble in water with a bluish-violet color and soluble in concentrated sulfuric acid of 66 Baume' with a bluish-black 'color, which is changed into red by the addition of ice. It yields upon reduction with stannous chlorid and hydrochloric acid triamidobenzene and 1. 8-dioxy-2-amido-naphthalene 3.6-disulfonic acid and dyes unmordanted wool bluish-black shades.

The process proceeds in an analogous manner on using other dioxynaphthalene disulfonic acids, such as l.S-diOXynaphthalene-QA- disulfonic acid, 1.5-dioxynaphthalene-3.7-disulfonic acid, or the like.

Having now described my invention and in what manner the same is to be performed, what I claim as new, and desire to secure by Letters Patent, is-

1. The herein-described new azo dyestuffs obtainable by first combining the diazo compound of mononitroacetyl-paraphenylenediamin having the above-given formula with dioxynaphthalene disulfonic acids and then s plitting oif the acetyl group by saponification, which dyestuffs are in the shape of their alkaline salts dark powders soluble in water, dyeing unmordanted wool black shades, and yielding upon reduction with stannous chlorid and hydrochloric acid triamidobenzene and amidodioxynaphthalene disulfonic acids, substantially as hereinbefore described.

2. The herein-described new dyestuff obtainable by first combining the diazo compound of mononitroacetyl-paraphenylenediamin having the above-given formula with 1. 8- dioxynaphthalene 3. 6-disulfonic acid and then splitting off the acetyl group by saponification, which dyestufl is in the shape of its so- 2-amid0naphthalene-3.G-disulfonic acid, sub- IO dium salt a dark powder soluble in Water with stantially as hereinbefcre described. a bluish-violet color, being dissolved by con- In testimony whereofIhave signed my name centrated sulfuric acid of 66 Baum with a in the presence of two subscribing Witnesses.

5 bluish-black color which is changed into red by the addition of ice, dyeing unmordanted MARTIN HLRABERLT' wool bluish-black shades, and yielding upon Witnesses: reduction with stannous ehlorid and hydro- OTTO KONIG,

chloric acid triamidobenzene and 1.8-dioxy- HEINR. AHLEFELDER. 

